Conventional printers use a label sheet with multiple labels arranged along a longitudinal direction of a long mount and detect the positions of the labels on the mount to perform a recording operation for the labels based on a detection result. Among such printers, some can use, as a recording object, multiple types of label sheets differing in the size and shape of the labels on the mount or in the arrangement intervals between labels.
Some printers that use multiple types of label sheets as a recording object are configured such that the position of a sensor that detects the positions of labels on a mount can be moved in a direction orthogonal to the conveyance direction of the label sheet so as to detect the positions of labels corresponding to the type of label sheet used as a recording object.
For example, according to a conventional technique, a sensor is coupled via an elastic member to a guide shaft extending in a direction orthogonal to the conveyance direction of the label sheet and the position of the sensor relative to the guide shaft is fixed by friction between the elastic member and the guide shaft while the sensor is made movable along the guide shaft against the friction (see, e.g., Patent Document 1).
For example, according to another conventional technique, a paper detection unit that includes a sensor is made movable along a longitudinal direction of a long hole disposed in a guide plate, and an inner circumferential surface of the long hole is provided with a concave/convex shape formed by alternately repeating convex and concave portions while an outer surface of the paper detection unit is provided with a protruding portion so as to transmit a click feeling to an operator from engagement of the protruding portion with the concave/convex shape accompanying movement of the paper detection unit, thereby giving the operator an indication of the position at which the paper detection unit should be stopped (see, e.g., Patent Document 2).    Patent Document 1: Japanese Laid-open Patent Publication No. 2003-146482    Patent Document 2: Japanese Laid-open Patent Publication No. 2012-148884